Photographic speed increasing and latent image stabilizing compounds, silver halide emulsions, and photographic elements

ABSTRACT

Photographic silver halide emulsions show increased speed and reduced latent image fading when a compound of the following structure is incorporated: ##STR1## wherein: X is --O--, --S--, --Se--, or ##STR2## Y represents the atoms completing a fused aromatic nucleus; Z is ##STR3##  and R is hydrogen or lower alkyl of from 1 to 5 carbon atoms.



